R&D Report 1962-01 : Tests of three systems of bandwidth compression of television signals G.F. Newell, W.K.E. Geddes This report describes an investigation into three similar methods of reducing the bandwidth required for the transmission of television pictures. The three methods all involve the isolation of the essential brightness changes in the picture; these are redistributed to occur at a uniform rate for transmission. A second signal must be transmitted in order to allow correct repositioning of the brightness changes in the final picture. Partial instrumentation has been carried out and the methods assessed as regards their bandwidth requirements and resultant picture quality.